Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Ryosuke Shimizu

Toshikazu Koudo

Noriaki Wakabayashi

Tsukasa Yoshiura

Tetsurou Takaoka

Takanori Okada

Shuichi Yoshida

Yoshiki Kuno

Noriaki Kubo

Jyun-ichi Komeno

Mitsuaki Oshima

Shinichi Tanaka

Hiromichi Ishibashi

Tatsuaki Ishida

Hajime Yamamoto

Kiyokazu Tohma

Keizo Miyata

Yoshio Umeda

Makoto Kuwamoto

Michiro Tanaka

Takumi Matsuura

Syuichi Yoshida

Satoshi Tan

An encryptor is provided for encrypting AV data sent from an interface. A controller controls recording of the encrypted AV data by controlling a recorder for recording the encrypted AV data in a magnetic disk. The recorder is controlled by the controller so as to reproduce the data recorded on the disk. A decrypter decrypts the reproduced data that is sent to the interface.

Recording apparatus, reproduction apparatus, data processing apparatus, recording and reproduction apparatus and data transmission apparatus and corresponding methods

A magnetic disk apparatus has: a head ( ) that performs data recording and playback while moving relative to a magnetic disk ( ) rotating at the prescribed speed; an actuator ( ) that positions said head relative to said magnetic disk ( ); and a controller ( ) that detects the position of said head by means of servo sector that have positioning information recorded magnetically on said magnetic disk ( ) and performs control to position said actuator ( ) by means of this detection signal, wherein said magnetic disk ( ) has at least a part in which the arrangement of tracks is spiral. The magnetic patterns on the disk include a servo sector and a data sector both formed on the same spiral track. The servo sector includes burst patterns for servo control.

Method and apparatus of forming a magnetic disk with a servo sector and a data sector on a spiral track

A disk-shaped recording medium includes a transparent substrate, and an optical recording layer and a magnetic recording layer formed at one side of the transparent substrate. An optical head applies light to the optical recording layer from a light source via the transparent substrate, and focuses the light on the optical recording layer and reproduces information from the optical recording layer. A magnetic head records information on the magnetic recording layer or reproduces information from the magnetic recording layer. An optical head moving device serves to move the optical head by a movement amount so as to focus the light on an optical track on the optical recording layer which has specified address information. A magnetic head moving device serves to move the magnetic head to a specified magnetic track on the magnetic recording layer by referring to the movement amount of the optical head.

Recording and reproducing apparatus with varying amounts of data in

In the head positioning apparatus of a disk-shaped information recording medium using the sector-servo-method, track codes are recorded in advance so as to be repeated every 12 tracks in the servo sectors of the disk-shaped information recording medium, the track are reproduced with a head, and a distance between the current position of the head and a target track is detected from the reproduced signal of the track codes with a resolution of 1/2.sup.7 of track width, then the head is moved to the target track so as to decrease the distance, when the head reaches the range of the width of .+-.6 tracks of the target track, an expanded head position signal having the resolution of 1/2.sup.7 is generated, and the head is controlled on the basis of the expanded head position signal and is finally settled to the target track.

Resolution enhancement of absolute track position using iterative

Track codes are recorded in advance so as to be repeated every 12 tracks, and burst signals .alpha. and .beta. are also recorded in advance so as to be repeated every 2 tracks, in the servo sectors of the disk-shaped information recording medium; the track codes and the burst signals .alpha. and .beta. are reproduced with a data head, and a distance between the current position of the data head and a target track is detected from the reproduced signal of the track codes with a resolution of 1/2.sup.2 of track width, then the data head is moved to the target track so as to decrease the distance; when the data head reaches the range of the width of .+-.6 tracks of the target track, an expanded data head position signal having the resolution of 1/2.sup.2 is generated; and thereby the data head is controlled.

A head position recognition method, a speed calculation method, and a head movement speed control device which provide for an overall improvement in storage device performance without increasing the seek time of the data head. Discrete servo sectors are provided circumferentially to the recording medium, four servo patterns with a minimum repeat cycle of 24 tracks are written into each servo sector. The range of the head seek distance that should be obtained at the current servo sector is estimated based on the previously calculated head seek distance, and the calculated head seek speed is corrected to the true head seek distance.

Head position recognition method, a speed calculation method, and a head

In a rotatable recording medium, three servo-patterns are discretely formed in the circular direction. A first servo-pattern is made of at least three-phase dibit patterns each having a period of 3 tracks; a second servo-pattern is made of two-phase dibit patterns having a period of 12 tracks and a shift of 3 tracks from each other; and a third servo-pattern is made of a dibit pattern having a period of 6 tracks and a shift of at least 1.5 tracks from the second servo-pattern. Based on reproduction signals derived from the three servo-patterns on the recording medium, relative position of a head against the recording medium is recognized with a precision up to (1/2.sup.N) of a track width using only a binary-valued process.

Apparatus and method for head-positioning on a rotatable recording medium

An optical disc drive apparatus has a remarkably improved track accessing ability in comparison with conventional like apparatus. On a base are provided an optical system having a light emitting element and a light sensing element, as well as an optical path deflecting element which performs a precision tracking. Further, an objective lens and a light guide element are provided on a rotating element which performs track seek and rough tracking. The light guide element comprises two reflecting members which are opposed in parallel with each other.

Optical disc drive apparatus

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Yawata, Japan

Ryosuke Shimizu